NFS Clients for NFS v3 and NFS v4.1 is built in to ESXi.
NFS can be used as a datastore to store ISO images, virtual machines and templates.
A NFS datastore can be mounted as read only to be used as a repository for ISO images or virtual machines templates.
NFS supports vMotion and Storage vMotion, HA and DRS, Fault Tolerance (FT not supported on NFS 4.1 datastores), virtual machine snapshots, and large capacity virtual disks.
Virtual disks created on NFS Datastores are thin-provisioned by default unless hardware acceleration which supports Reserve Space operation is used.
NFS v4.1 does not support hardware acceleration.

Supports storage devices greater than 2 TB.
Supports virtual machine disks greater than 2 TB.
Standard 1 MB file system block size.
Ability to reclaim physical storage space on thin provisioned storage devices.
Online upgrade process allows VMFS datastores to be upraded without disrupting hosts or virtual machines.
New VMFS datastores are created with the GPT format.
An upgraded VMFS datastore will continue to use the MBR format until it is expanded beyond 2TB. Once expanded beyond 2TB the MGS format is converted to GPT.
Supports up to 256 VMFS datastores per host

Upgrading VMFS Datastores in the vSphere Storage Guide on page 164.
Before upgrading a datastore to VMFS5 ensure all hosts support VMFS5 (running ESXi 5.0 or newer).
VMFS5 upgrade is a one way process. Once upgraded to VMFS5 the datastore cannot reverted back to the previous VMFS format.
VMFS3 to VMFS5 datastore upgrade can be performed while the datastore is in use.

No virtual machines in the hosts’ inventory should reside on the datastore

The datastore should not be used for HA heartbeats

The datastore is not managed by Storage DRS

Storage IO control is disabled on the datastore

A VMFS datastore that has been unmounted from all hosts remains in inventory, but is marked as inaccessible.

Delete a VMFS Datastore using the Web Client -> Storage -> Datastore
Right click the datastore and select Delete Datastore.

Remove VMFS Datastores in the vSphere Storage Guide on page 169.
When you delete a datastore, it is destroyed and disappears from all hosts that have access to the datastore.
The VMFS datastore can be deleted while mounted. It is preferable to unmount the VMFS datastore from all hosts prior to deleting it.
Before removing a VMFS Datastore:

Remove or migrate all virtual machines from the datastore

Ensure no other hosts are accessing the datastore

Disable Storage DRS for the datastore

Disable Storage IO control on the datastore

Make sure the datastore is not used for HA heartbeating

– Mount/Unmount an NFS Datastore
Create a NFS Datastore in the vSphere Storage Guide on page 161.
New NFS Datastore
Select the NFS Version – NFS 3 or NFS 4.1 – Use only one NFS version to access a given datastore.
Provide the Datastore Name, Folder, and Server (IP or FQDN).
NFS datastores can be mounted as read-only.

Use Mount Datastore to Additional Hosts to mount the NFS datastore to other hosts in vCenter inventory.
NFS Datastores can be mounted or unmounted from multiple hosts using the vSphere Web Client.

When an NFS datastore has been unmounted from all hosts it disappears from inventory.
Use the New Datastore wizard to mount an NFS datastore which has been removed from inventory.

If the device has available adjacent capacity the expandable column will show Yes and the extent will be expanded. Otherwise an available device will be added as a new extent.
The datastore can then be extended into the available space.

Raw device mapping (RDM) provides a mechanism for a virtual machine to have direct access to a LUN on the physical storage subsystem.
An RDM is a mapping file in a separate VMFS volume that acts as a proxy for a raw physical storage device.

RDM is used in the following situations:

When SAN snapshot or other layered applications run in the virtual machine. The RDM better enables scalable backup offloading systems by using features inherent to the SAN.

In any MSCS clustering scenario that spans physical hosts — virtual-to-virtual clusters as well as physical-to-virtual clusters. In this case, cluster data and quorum disks should be configured as RDMs rather than as virtual disks on a shared VMFS.

Physical Compatibility Mode
In physical mode, the VMkernel passes all SCSI commands to the device, with one exception: the REPORT LUNs command is virtualized so that the VMkernel can isolate the LUN to the owning virtual machine. All physical characteristics of the underlying hardware are exposed.
Allows the guest operating system to access the hardware directly.
A virtual machine with a physical compatibility RDM cannot be cloned, made into a template, or migrated if the migration involves copying the disk.

Virtual Compatibility Mode
In virtual mode, the VMkernel sends only READ and WRITE to the mapped device. The mapped device appears to the guest operating system exactly the same as a virtual disk file in a VMFS volume. The real hardware characteristics are hidden.
Allows the RDM to behave as if it were a virtual disk, so you can use such features as taking snapshots, cloning, and so on.
When an RDM disk in virtual compatibility mode is cloned or a template is created out of it, the contents of the LUN are copied into a .vmdk virtual disk file.

– Select the Preferred Path for a VMFS Datastore
Change the Path Selection Policy in the vSphere Storage Guide on page 191.

When using Fixed path policy the preferred path is marked with an asterisk (*) in the preferred column.

When using the Fixed path policy a designated preferred path can be selected or the first working path if a preferred path has not be set. Fixed is the default policy for most active-active storage devices.

– Disable a path to a VMFS Datastore
Disable Storage Paths in the vSphere Storage Guide on page 192.
Paths can be temporarily disabled fro maintenance. Paths can be disabled in the Web Client from the datastore, storage device, or adapter view.

vHersey

Hersey Cartwright is an IT professional with extensive experience designing, implementing, managing, and supporting technologies that improve business processes. Hersey is Solutions Architect for HPE SimpliVity covering Virginia, Washington DC, and Maryland. He holds the VMware Certified Design Expert (VCDX-DV #128) certification. Hersey actively participates in the VMware community and was awarded the VMware vExpert title in 2016, 2015, 2014, 2013, and 2012. He enjoys working with, teaching, and writing about virtualization and other data center technologies. Follow Hersey on Twitter @herseyc